a try

src/day14/main.rs

@@ -1,4 +1,3 @@
-use std::borrow::{Borrow, BorrowMut};
 use std::collections::HashMap;
 use std::convert::*;
 use std::fs::File;
@@ -25,7 +24,6 @@ impl From<(Vec<Resource>, usize)> for ResourceBuilder {
 #[derive(Default, Debug)]
 struct NanoFactory {
     pipeline: Pipeline,
-    storage: HashMap<Resource, usize>,
 }
 
 #[derive(Debug)]
@@ -38,46 +36,74 @@ enum NanoFactoryBuildState {
 }
 
 impl NanoFactory {
-    fn generate_fuel(&mut self) -> usize {
-        let storage = self.storage.borrow_mut();
-        let pipeline = self.pipeline.borrow();
-        return NanoFactory::lookup_resource(storage, pipeline, "FUEL");
+    fn generate_fuel(&self) -> usize {
+        let mut storage: HashMap<Resource, usize> = HashMap::new();
+        self.lookup_resource(&mut storage, "FUEL")
     }
 
-    fn lookup_resource(
-        storage: &mut HashMap<Resource, usize>,
-        pipeline: &Pipeline,
-        resource: &str,
-    ) -> usize {
+    fn generate_fuel_from_ores(&self, ores: usize) -> usize {
+        let mut storage: HashMap<Resource, usize> = HashMap::new();
+        let mut fuel_for_even = 0;
+        let mut ores_for_even = 0;
+        loop {
+            fuel_for_even += 1;
+            ores_for_even += self.lookup_resource(&mut storage, "FUEL");
+            if storage.iter().all(|(_, v)| *v == 0) {
+                break;
+            }
+        }
+        println!(
+            "fuels_for_even:{} ores_for_even:{}",
+            fuel_for_even, ores_for_even
+        );
+        let steps = ores / ores_for_even;
+        println!("{}", steps);
+        let mut fuel = fuel_for_even * steps;
+        let mut ores = ores - (ores_for_even * steps);
+        loop {
+            let cost = self.lookup_resource(&mut storage, "FUEL");
+            if cost > ores {
+                break;
+            }
+            ores -= cost;
+            fuel += 1;
+        }
+        fuel
+    }
+
+    fn lookup_resource(&self, storage: &mut HashMap<Resource, usize>, resource: &str) -> usize {
         if resource == "ORE" {
             return 1;
         }
 
         // use from storage
-        if let Some(count) = storage.get_mut(resource.into()) {
+        if let Some(count) = storage.get_mut(resource) {
             if *count > 0 {
                 *count -= 1;
                 return 0;
             }
         }
 
-        // cloned to still allow writable acces to self
-        let required = pipeline
-            .get(resource.into())
-            .expect("unable to find resource");
-
         // initialize storage with zero
-        if let None = storage.get(resource.into()) {
+        if storage.get(resource).is_none() {
             storage.insert(resource.into(), 0);
         }
 
         // build resource and and to storage
-        let stored = storage.get_mut(resource.into()).unwrap();
-        *stored += required.out_count - 1;
-        required.requirements.iter().fold(0, |mut acc, c| {
-            acc += NanoFactory::lookup_resource(storage, pipeline, c);
+        let required = self
+            .pipeline
+            .get(resource)
+            .expect("unable to find resource");
+        let cost = required.requirements.iter().fold(0, |mut acc, c| {
+            acc += self.lookup_resource(storage, c);
             acc
-        })
+        });
+
+        // update storage
+        let stored = storage.get_mut(resource).unwrap();
+        *stored += required.out_count - 1;
+
+        cost
     }
 }
 
@@ -182,9 +208,12 @@ where
 fn main() {
     let f = File::open("input14").unwrap();
     let bufreader = BufReader::new(f);
-    let mut factory = NanoFactory::from(bufreader);
-    let ores = factory.generate_fuel();
-    println!("ores: {}", ores);
+    let factory = NanoFactory::from(bufreader);
+    println!("ores: {}", factory.generate_fuel());
+    println!(
+        "ores: {}",
+        factory.generate_fuel_from_ores(1_000_000_000_000)
+    );
 }
 
 #[cfg(test)]
@@ -204,9 +233,8 @@ mod tests {
             .trim()
             .as_bytes(),
         );
-        let mut factory = NanoFactory::from(bufreader);
-        let ores = factory.generate_fuel();
-        assert_eq!(ores, 31)
+        let factory = NanoFactory::from(bufreader);
+        assert_eq!(factory.generate_fuel(), 31);
     }
 
     #[test]
@@ -224,9 +252,8 @@ mod tests {
             .trim()
             .as_bytes(),
         );
-        let mut factory = NanoFactory::from(bufreader);
-        let ores = factory.generate_fuel();
-        assert_eq!(ores, 165)
+        let factory = NanoFactory::from(bufreader);
+        assert_eq!(factory.generate_fuel(), 165)
     }
 
     #[test]
@@ -246,9 +273,9 @@ mod tests {
             .trim()
             .as_bytes(),
         );
-        let mut factory = NanoFactory::from(bufreader);
-        let ores = factory.generate_fuel();
-        assert_eq!(ores, 13312)
+        let factory = NanoFactory::from(bufreader);
+        assert_eq!(factory.generate_fuel(), 13312);
+        assert_eq!(factory.generate_fuel_from_ores(1_000_000_000_000), 82892753);
     }
 
     #[test]
@@ -271,9 +298,9 @@ mod tests {
             .trim()
             .as_bytes(),
         );
-        let mut factory = NanoFactory::from(bufreader);
-        let ores = factory.generate_fuel();
-        assert_eq!(ores, 180697)
+        let factory = NanoFactory::from(bufreader);
+        assert_eq!(factory.generate_fuel(), 180697);
+        assert_eq!(factory.generate_fuel_from_ores(1_000_000_000_000), 5586022);
     }
 
     #[test]
@@ -301,8 +328,8 @@ mod tests {
             .trim()
             .as_bytes(),
         );
-        let mut factory = NanoFactory::from(bufreader);
-        let ores = factory.generate_fuel();
-        assert_eq!(ores, 2210736)
+        let factory = NanoFactory::from(bufreader);
+        assert_eq!(factory.generate_fuel(), 2210736);
+        assert_eq!(factory.generate_fuel_from_ores(1_000_000_000_000), 460664);
     }
 }